Investigation of the possibility of shaping an electron dose field of a clinical accelerator with 3D printed polymer products

Abstract

The improvement of existing dose delivery techniques is a constant goal in cancer radiation therapy, since it increases the treatment efficiency. For example, the use of so-called boluses and compensators offers ways to correct for surface irregularities or tissue inhomogeneities in some irradiated areas. While compensators are usually inserted along the radiation beam at a certain distance from the patient, boluses are located directly on the surface of the patient's body and follow its contours. Depending on their thickness and shape, these beam modifiers enable a shift of the depth of the dose maximum and control the depth-dose distribution. However, an accurate production of beam modifiers often requires complex procedures, thus limiting their use in the clinic. This study suggests the fused filament fabrication technique to produce polymer-based beam modifiers for shaping the dose of clinical electron beams. The feasibility of this approach was studied through a series of experiments and simulations using the Monte Carlo method. The results show that therapeutic electron beams with energies of 6–12 MeV can be effectively modified using such polymer samples. The numerical model can also be used to evaluate the dose distribution of electron beams shaped by plastic absorbers prior to production, thereby making it possible to select the compensator geometry for specific purposes.